This invention relates generally to the field of energy and more specifically to methods and apparatus for an improved hydropower system.
There are a variety of prior art systems for extracting power from water based systems such as dams, rivers and ocean flows. Several patents disclose a variety of after market retrofits for extracting hydropower from river flow by inserting additional equipment at the base of the dam to take advantage of the head potential present behind the dam. For example, U.S. Pat. Nos. 4,073,146, 4,078,388, 4,117,676, 4,159,188, 4,165,467, 4,170,428, 4,261,171, 4,279,539, and 4,468,153 show a retrofit system for extracting energy out of the head potential of a dam. None of these patents shows the innovative combination of the present invention and its use for increased extraction of kinetic flow energy in a downstream system and innovative method of increasing flow velocity for kinetic hydropower.
One of the current problems facing hydrokinetic power producers when locating hydrokinetic turbines downstream of existing dams is that the design of the draft tube at an existing dam (the draft tube conducts water from the outlet of the turbine to the body of water downstream of the existing dam) is specifically designed to dissipate kinetic energy. That is to say, the draft tube is a diffuser. The diffuser sometimes takes the shape of a frustoconical or an elliptically shaped frustoconical due to underwater bathymetry. The end result of the draft tube diffuser is that the kinetic energy of the water is lowered, meaning the water velocity is slowed. An additional problem that hydrokinetic power producers face at dams is that many tailrace designs dump water from the outlet of the draft tube into an open body of water, such as a lake, reservoir, pool, or river to additionally dissipate the kinetic energy of the water in the tailrace exiting the draft tube.